Ruby is 17. Starting at age 9, she began noticing the skin on her neck and arms looked dirty or stained, but no amount of scrubbing got rid of it. When she saw her doctor, she found out she had acanthosis nigricans — a condition in which the skin thickens and darkens in places.

Ruby found out that staying at a healthy weight made the condition less noticeable. Just learning what was going on and what she could do really helped.

What Is Acanthosis Nigricans?

The name is hard to pronounce (ay-can-THO-sis NYG-ruh-cans), but if you have AN, you're probably more concerned about how it looks. You'll notice that your skin is thicker and darker, especially around joints and areas with lots of creases and folds, like your knuckles, armpits, elbows, knees, and neck.

Some people see thicker, darker skin on the palms of their hands, inner thighs, groin, lips, or other areas. The skin usually stays soft, which is why the word "velvety" is often used to describe the symptoms of acanthosis nigricans.

AN is most common in people of African, Caribbean, and Hispanic descent but anyone can have it. Many people who develop AN have no other symptoms and are otherwise healthy. But because AN can be a sign of certain other medical conditions, it's a good idea for it to be checked out by a doctor.

What Causes AN?

People who are overweight or obese are more likely to develop AN, which often lessens or goes away with weight loss. Some people with the condition inherit it. Certain medicines — for example, birth control pills or hormone treatments — also can cause AN.

Sometimes, it's seen in people who have type 2 diabetes or who are at greater risk for getting this type of diabetes. In these cases, acanthosis nigricans itself isn't dangerous. But it can be a sign to doctors to check someone for diabetes or other health problems. Sometimes, finding and treating the health problem might make the person's skin condition improve or clear up.

Almost 75% of kids with type 2 diabetes develop AN, according to the American Diabetes Association. For many, getting their diabetes and weight (if they are overweight) under control goes a long way toward lessening the visibility of AN.

What to Do

First of all, don't panic. Acanthosis nigricans itself is not harmful or contagious but you should see a doctor to make sure it's not caused by something that does need attention. In some cases, AN can be a signal that you're at risk for diabetes. Whenever you notice a change in the color, thickness, or texture of your skin, it's wise to see a health professional.

What to Expect

If you're diagnosed with AN, your doctor might want you to have a blood test or other tests to try to determine what's causing it or to look for other conditions (like type 2 diabetes) that occur more often in people with AN.

Treatment for AN

If your doctor determines that your AN is not connected to a more serious medical condition, you don't need to treat it. But you might want to if your doctor thinks there is a way to help improve the appearance of your skin. Sometimes, AN fades on its own.

Your doctor may prescribe lotions or creams. Ask as many questions as you need to in order to understand when and how to follow the treatment plan.

It's easy to fall into believing the hype about bleaches, skin scrubs, and over-the-counter exfoliating treatments. But these aren't likely to work and can irritate your skin, not to mention waste money and sometimes just boost your stress about AN!

Maintaining a healthy weight by staying physically active and eating well can help prevent or treat acanthosis nigricans in some cases.

You also should make plans to take care of yourself in other ways. Because this condition is visible, some people with acanthosis nigricans feel self-conscious or embarrassed about the way their skin looks. It can help to talk to a counselor, doctor, friend, or even peer support group to help you feel more confident. Your doctor or nurse probably can help you find local or online support groups. And don't be afraid to talk to your friends. Good friends are the best support!

Reviewed by: Patrice Hyde, MD
Date reviewed: April 2013